my sink spits

second floor laundry is next to a bathroom. Got a new LG washer in the spring, just noticed that the sink
faucet spits like the water was turned on and off, except it wasn't. (have private well and septic) Today
heard the washer make two brief "gag" sounds about 5 minutes after starting. Went in the adjacent bathroom
and the faucet spit water and air when I turned it on. Could my roof stack be clogged somehow, or is there
a more logical explanation? Our previous 20yr old washer never made a peep, except when the tub was out of
balance and the buzzer could be heard from the next township.

appreciate any help.

BenE

You are running out of water from your well tank,
you need a plumber or well driller to check out your system,
before you possible run out of water, it could be problem with pressure tank, well pump, or water level in well
dropping below the pump pickup,
the washer is drawing the tank down causing air in the pipes

Obviously, unless your water and drain systems are connected together, there is NO possibility that a clogged vent, or ANYTHING ELSE, will cause a problem with the faucet's water. You have an entirely different problem and the only way to do a proper diagnosis is to be there and do our own testing.

As hj said, the sewer should most certainly not be connected to the well pump so unrelated.

You need to describe your well and pump system. Is it a bladder or hydro-pneumatic tank? Deep or shallow well pump? Jet or submersible? Air injection water treatment? Air is getting into the system either deliberately or not. If deliberately, then the AVC or air separator might not be working.

Yesterday my wife had two watering hoses on the go when the timers for the soakers came on. The combined draw was more than the pump could keep up with and the pressure dropped well below the kick-in setting. As a result, the level in the hydro-pneumatic tank dropped low enough that the air escaped into the line causing air to spurt out of the hoses. The AVC on the tank would normally bleed off excess air but it does so at a slow rate and it was overwhelmed by the sudden drop in level.